In many current applications, track chain members such as track links or track shoes, or track pads, are attached to each other using a pin that allows the track chain members to rotate relative to each other while still allowing the chain to remain in tension when installed on the undercarriage of a track type vehicle. For heavy equipment, such as electric rope shovels and the like, track pads which incorporates the track rail and track shoe in a single, unitary body are used. In some applications the track pads are required to support the heavy load of the machine on soft surfaces such as oil sand and the like.
Due to the lack of support on soft surfaces and/or packing of the soft material such as oil sand into the cavities of the track pad, the track pad may develop cracks, or experience pitch extension (elongation of the track pad), necessitating repair.
Various track pad geometries are known in the art including the track pad geometry disclosed in U.S. Pat. No. 9,446,802 to Oliver Weiβ et al. The '802 patent discloses a track pad for a chain of a chain wheel drive, the track pad having a bearing surface provided with at least one grouser (1, 2), extending in the lateral direction of the bearing surface, wherein at least one flat part (4, 5) is provided next to at least one grouser part (1, 2) in the lateral direction of the bearing surface. Further, the invention comprises a track pad for a chain of a chain wheel drive, the track pad having a bearing surface provided with at least one grouser (32, 33) protruding from a base plate (40), the grouser (32, 33) extending in the lateral direction of the bearing surface, wherein the bearing surface of the base plate has a profile in the lateral direction. As can be seen, the '802 patent is directed to reducing the shearing forces within the track chain when the machine moves around a corner caused by the grip provided by the grousers.
Accordingly, there is a need to develop a track pad when used on soft surfaces that is more robust than has heretofore been devised.